To meet the fast growing demand in mobile data service, various network operators are developing new technologies and defining new standards for the next generation wireless networks to achieve much higher peak transmission rate. For example, 1 Gbps peak transmission rate is required by ITU-R for IMT-Advanced systems in the 4th generation (“4G”) mobile communications systems. 1 Gbps peak transmission rate in wireless networks can provide users similar experience as in wireline networks, and it is sufficient to satisfy most applications on the Internet today and in the near future.
While peak transmission rate is no longer a critical problem after 4G era, network capacity is likely to be exhausted very soon in the next few years. Not only traffic demand is growing dramatically (i.e., >50× in 5 years), but also the improvement on average cell spectral efficiency is very limited from 3G to 4G era (i.e., <10×). In addition, the available spectrum resource is also limited. Network capacity will still be exhausted very soon even all the networks are upgraded with 4G air interface. This problem in fact already happens in some areas. Therefore, capacity exhaustion is anticipated to be the most critical problem.
While the demand on wireless communication service continues to increase, the demand on broadband access may not always require mobility support. In fact, studies have shown that only a small fraction of users demand on simultaneous mobile and broadband access. Therefore, in addition to cellular networks, there are other networks able to deliver information to mobile users, with or without mobility support. In most geographic areas, multiple radio access networks (RANs) such as E-UTRAN and WLAN are usually available. Furthermore, wireless communication devices are increasingly being equipped with multiple radio transceivers for accessing different radio access networks. For example, a multiple radio terminal (MRT) may simultaneously include Bluetooth, WiMAX, and WiFi radio transceivers. Thus, multi-radio integration becomes more feasible today and is the key to help user terminals to explore more bandwidth available from different radio access technologies and achieve better utilization of scarce radio spectrum resources.
There is currently no specified prior art that performs traffic offload to WiFi for a cellular UE that takes cellular load into account, or gives the Cellular Radio Access Network the possibility to control to what extent traffic of UEs in a certain cell is offloaded to WiFi. Furthermore, it is currently not possible for the Cellular RAN to identify and pick particular UEs for traffic offload to WiFi.
The current art for WiFi offload, for example, 3GPP ANDSF assumes various level of support for traffic offload. All traffic of a UE, all traffic towards a certain APN, or individual IP flows can be offloaded. A requirement is that even though offload to WiFi is being done, it shall be possible to keep some traffic on Cellular, e.g. real-time critical traffic, certain IMS traffic, emergency call. Another requirement is that it shall be possible to do load dependent or RAN controlled offloading without ANDSF framework. A problem then is that offloading should preferably be done on APN or IP flow level, but in the current 3GPP architecture, the RAN has no knowledge of APNs or IP flows.